Just yesterday, the Cassini spacecraft passed an incredible 25 kilometers (16 miles) off the surface of Saturn’s weird moon Enceladus. This icy ball has plumes of water jetting up from its south pole region, emanating from a series of parallel cracks nicknamed tiger stripes. Cassini flew right through these plumes! The images taken have not been fully processed yet, but the Cassini folks have released a few of the raw images. Here’s one:

Wow. The surface of Enceladus is entirely covered with ice; see how few craters there are? That means the surface is "new"; if it were older there would be lots more craters. That means the moon is recently (or continuously) resurfaced, which in turn means a dynamic process almost certainly involving water and a liquid interior. The cracks and plates look to be due to ice floes. We see the same sort of thing here on Earth and on Jupiter’s frozen moon Europa.